San Francisco's most recent litter charcterization study shows that polystyrene takeout food packaging is no longer a large component of the city's litter. John Upton writes in the San Francisco Examiner:

The ban appears to have had a significant impact: Researchers drafting an annual litter report have found the amount of polystyrene foam strewn across The City fell 36 percent in the last year, according to San Francisco commercial recycling coordinator Jack Macy. Much of the remaining polystyrene foam that litters The City comes from packing material and from instant noodles and other products sold at grocery stores, according to Macy.